There are obviously two engine gasket sets, one for metal engine cylinder cover and the other for the plastic cover.
Genuine GM part numbers are:
1 - Engine Gasket Set for Metal Cylinder Head Cover - part # 9194778
8 - Engine Gasket Set for Plastic Cylinder Head Cover - part # 93181942
The individual gasket part no's in the sets are identical except for the cylinder head cover gaskets as listed in post #2.
If you need to verify any part numbers for reference, check out the 'Part Numbers' section in the forum or post a thread there.